Scientists at Colorado State University (CSU), including Elizabeth Pilon-Smith, have spent decades pondering how plants can help clean the soil. A CSU student summary of hemp phytoremediation gives a nice review of that we know so far (2012), including links to peer-reviewed studies on the subject.

Source: https://www.rxleaf.com/hemp-cleans-up-radioactive-soil-and-so-much-more/